PHYSIOLOGY AND EXPERIMENTAL PATHOLOGY 733 



causes polyuria. This lies at the level of the gray substance of the tuber 

 cinereum near the infundibulum. A lesion in front of this zone at the 

 level of the chiasm or back of it at the level of the protuberance is not 

 followed by polyuria. 



Hanchett has made some interesting observations in this connection. 

 He attempted to produce polyuria in animals. Electrical stimulation and 

 heat did not avail. Polyuria could, however, be produced almost in- 

 variably by removing the floor of the sella and allowing the hypophysis to 

 prolapse into the pharynx. This operation with its attendant pull upon 

 the infundibulum gave rise more constantly to polyuria than any other 

 type of operation. 



A peculiar effect of spinal puncture upon diabetes insipidus has 

 been observed by Herrick and Cammidge. The patient observed by 

 Herrick reacted rather violently after a spinal puncture, but the urinary 

 output rapidly decreased within twenty-four hours, with a marked in- 

 crease in specific gravity. The reduced urinary output continued for 

 some three months when the polyuria again developed. Cammidge's 

 patient, suffering with diabetes insipidus, has apparently remained cured 

 since the spinal puncture. In neither of these cases could a hypophyseal 

 tumor be found. 



Clinical evidence indicating that diabetes insipidus may be associated 

 with lesions about the hypophysis and floor of the third ventricle is 

 abundant. In about 7 per cent, of the cases, of interpeduncular tumors so 

 frequently associated with Frohlich's syndrome the patients have some 

 time during the clinical course diabetes insipidus. Bullets lodged in this 

 position, secondary carcinomas of the infundibulum, and basal skull frac- 

 tures involving the area above mentioned not infrequently give rise to 

 polyuria. 



This polyuria was naturally supposed to be due to increased secretion 

 of the pars intermedia when these extracts were shown by Magnus and 

 Schaefer to have a diuretic action. Recent work seems to indicate that 

 the cause of this polyuria is not dependent upon altered or increased secre- 

 tion of the pars intermedia. The control of diabetes insipidus by pituitrin 

 speaks forcibly at least against overactivity of the cells of the pars inter- 

 media as the cause of this disease. 



As hypophyseal extracts and epinephrin have so many actions in 

 common it was quite natural to suppose that they might have a similar 

 effect upon sugar metabolism. 



Experimental work which has been done, especially by Gushing and 

 his school, would seem to indicate that overactivity of the pars intermedia 

 might be followed by a decreased sugar tolerance, giving rise to glycosuria, 

 so frequently observed in acromegalics. Lessened or inhibited secretion of 

 the pars intermedia would give rise to increased sugar tolerance. This 



